Question

1. car a and car b have the same mass. which car would have the larger kinetic energy if car a is traveling at 80 mph and car b is traveling at 80 mph?

car a
car b
both cars have the same kinetic energy.
neither car has kinetic energy.

Explanation:

Step1: Recall the kinetic energy formula

The formula for kinetic energy is \(K = \frac{1}{2}mv^{2}\), where \(m\) is the mass and \(v\) is the velocity.

Step2: Compare the velocities

Given that \(m_{A}=m_{B}\) (same mass). Let \(m = m_{A}=m_{B}\), \(v_{A} = 80\) mph and \(v_{B}=60\) mph.
For car A, \(K_{A}=\frac{1}{2}mv_{A}^{2}=\frac{1}{2}m\times(80)^{2}=\frac{1}{2}m\times6400 = 3200m\)
For car B, \(K_{B}=\frac{1}{2}mv_{B}^{2}=\frac{1}{2}m\times(60)^{2}=\frac{1}{2}m\times3600 = 1800m\)

Since \(3200m>1800m\) (because \(m>0\)), car A has larger kinetic energy.

Answer:

Car A